RE: [RFC v2 07/11] hv_netvsc: Use HV_HYP_PAGE_SIZE for Hyper-V communication

[Michael Kelley]

From: Boqun Feng <boqun.feng@xxxxxxxxx> Sent: Tuesday, September 1, 2020 8:01 PM
> 
> When communicating with Hyper-V, HV_HYP_PAGE_SIZE should be used since
> that's the page size used by Hyper-V and Hyper-V expects all
> page-related data using the unit of HY_HYP_PAGE_SIZE, for example, the
> "pfn" in hv_page_buffer is actually the HV_HYP_PAGE (i.e. the Hyper-V
> page) number.
> 
> In order to support guest whose page size is not 4k, we need to make
> hv_netvsc always use HV_HYP_PAGE_SIZE for Hyper-V communication.
> 
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> ---
>  drivers/net/hyperv/netvsc.c       |  2 +-
>  drivers/net/hyperv/netvsc_drv.c   | 46 +++++++++++++++----------------
>  drivers/net/hyperv/rndis_filter.c | 12 ++++----
>  3 files changed, 30 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index 41f5cf0bb997..1d6f2256da6b 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -794,7 +794,7 @@ static void netvsc_copy_to_send_buf(struct netvsc_device
> *net_device,
>  	}
> 
>  	for (i = 0; i < page_count; i++) {
> -		char *src = phys_to_virt(pb[i].pfn << PAGE_SHIFT);
> +		char *src = phys_to_virt(pb[i].pfn << HV_HYP_PAGE_SHIFT);
>  		u32 offset = pb[i].offset;
>  		u32 len = pb[i].len;
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 64b0a74c1523..61ea568e1ddf 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -373,32 +373,29 @@ static u16 netvsc_select_queue(struct net_device *ndev, struct
> sk_buff *skb,
>  	return txq;
>  }
> 
> -static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
> +static u32 fill_pg_buf(unsigned long hvpfn, u32 offset, u32 len,
>  		       struct hv_page_buffer *pb)
>  {
>  	int j = 0;
> 
> -	/* Deal with compound pages by ignoring unused part
> -	 * of the page.
> -	 */
> -	page += (offset >> PAGE_SHIFT);
> -	offset &= ~PAGE_MASK;
> +	hvpfn += offset >> HV_HYP_PAGE_SHIFT;
> +	offset = offset & ~HV_HYP_PAGE_MASK;
> 
>  	while (len > 0) {
>  		unsigned long bytes;
> 
> -		bytes = PAGE_SIZE - offset;
> +		bytes = HV_HYP_PAGE_SIZE - offset;
>  		if (bytes > len)
>  			bytes = len;
> -		pb[j].pfn = page_to_pfn(page);
> +		pb[j].pfn = hvpfn;
>  		pb[j].offset = offset;
>  		pb[j].len = bytes;
> 
>  		offset += bytes;
>  		len -= bytes;
> 
> -		if (offset == PAGE_SIZE && len) {
> -			page++;
> +		if (offset == HV_HYP_PAGE_SIZE && len) {
> +			hvpfn++;
>  			offset = 0;
>  			j++;
>  		}
> @@ -421,23 +418,26 @@ static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
>  	 * 2. skb linear data
>  	 * 3. skb fragment data
>  	 */
> -	slots_used += fill_pg_buf(virt_to_page(hdr),
> -				  offset_in_page(hdr),
> -				  len, &pb[slots_used]);
> +	slots_used += fill_pg_buf(virt_to_hvpfn(hdr),
> +				  offset_in_hvpage(hdr),
> +				  len,
> +				  &pb[slots_used]);
> 
>  	packet->rmsg_size = len;
>  	packet->rmsg_pgcnt = slots_used;
> 
> -	slots_used += fill_pg_buf(virt_to_page(data),
> -				offset_in_page(data),
> -				skb_headlen(skb), &pb[slots_used]);
> +	slots_used += fill_pg_buf(virt_to_hvpfn(data),
> +				  offset_in_hvpage(data),
> +				  skb_headlen(skb),
> +				  &pb[slots_used]);
> 
>  	for (i = 0; i < frags; i++) {
>  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
> 
> -		slots_used += fill_pg_buf(skb_frag_page(frag),
> -					skb_frag_off(frag),
> -					skb_frag_size(frag), &pb[slots_used]);
> +		slots_used += fill_pg_buf(page_to_hvpfn(skb_frag_page(frag)),
> +					  skb_frag_off(frag),
> +					  skb_frag_size(frag),
> +					  &pb[slots_used]);
>  	}
>  	return slots_used;
>  }
> @@ -453,8 +453,8 @@ static int count_skb_frag_slots(struct sk_buff *skb)
>  		unsigned long offset = skb_frag_off(frag);
> 
>  		/* Skip unused frames from start of page */
> -		offset &= ~PAGE_MASK;
> -		pages += PFN_UP(offset + size);
> +		offset &= ~HV_HYP_PAGE_MASK;
> +		pages += HVPFN_UP(offset + size);
>  	}
>  	return pages;
>  }
> @@ -462,12 +462,12 @@ static int count_skb_frag_slots(struct sk_buff *skb)
>  static int netvsc_get_slots(struct sk_buff *skb)
>  {
>  	char *data = skb->data;
> -	unsigned int offset = offset_in_page(data);
> +	unsigned int offset = offset_in_hvpage(data);
>  	unsigned int len = skb_headlen(skb);
>  	int slots;
>  	int frag_slots;
> 
> -	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
> +	slots = DIV_ROUND_UP(offset + len, HV_HYP_PAGE_SIZE);
>  	frag_slots = count_skb_frag_slots(skb);
>  	return slots + frag_slots;
>  }
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index b81ceba38218..acc8d957bbfc 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -25,7 +25,7 @@
> 
>  static void rndis_set_multicast(struct work_struct *w);
> 
> -#define RNDIS_EXT_LEN PAGE_SIZE
> +#define RNDIS_EXT_LEN HV_HYP_PAGE_SIZE
>  struct rndis_request {
>  	struct list_head list_ent;
>  	struct completion  wait_event;
> @@ -215,18 +215,18 @@ static int rndis_filter_send_request(struct rndis_device *dev,
>  	packet->page_buf_cnt = 1;
> 
>  	pb[0].pfn = virt_to_phys(&req->request_msg) >>
> -					PAGE_SHIFT;
> +					HV_HYP_PAGE_SHIFT;
>  	pb[0].len = req->request_msg.msg_len;
>  	pb[0].offset =
> -		(unsigned long)&req->request_msg & (PAGE_SIZE - 1);
> +		(unsigned long)&req->request_msg & (HV_HYP_PAGE_SIZE - 1);

Use offset_in_hvpage() as defined in patch 6 of the series?

> 
>  	/* Add one page_buf when request_msg crossing page boundary */
> -	if (pb[0].offset + pb[0].len > PAGE_SIZE) {
> +	if (pb[0].offset + pb[0].len > HV_HYP_PAGE_SIZE) {
>  		packet->page_buf_cnt++;
> -		pb[0].len = PAGE_SIZE -
> +		pb[0].len = HV_HYP_PAGE_SIZE -
>  			pb[0].offset;
>  		pb[1].pfn = virt_to_phys((void *)&req->request_msg
> -			+ pb[0].len) >> PAGE_SHIFT;
> +			+ pb[0].len) >> HV_HYP_PAGE_SHIFT;
>  		pb[1].offset = 0;
>  		pb[1].len = req->request_msg.msg_len -
>  			pb[0].len;
> --
> 2.28.0